The Fifth Doctor and Tegan reunite after 38 years in Doctor Who special

David Bradley, Colin Baker, Sylvester McCoy, Paul McGann and Peter Davison all reappeared in a sequence that saw the Thirteenth Doctor (Jodie Whittaker) fighting against a forced regeneration, with these past incarnations existing as "guardians of the edge" within a mindscape that Time Lords cross in the final seconds of the process.

But that wasn't the extent of the classic Doctors' contribution – having covertly implanted her friends with an implant, the Doctor was able to appear to assist her friends by way of a hologram generated by the TARDIS, despite being trapped at the "edge of existence".

The hologram came to Tegan's aid as she found herself trapped within the new UNIT HQ as it was swarmed by Cybermen – and her "emotional memory" was seen to affect the hologram's interface, with its appearance switching from the Thirteenth Doctor to the Fifth.

"You sort of look like you used to, but not quite," Tegan says to her Doctor. "I could say the same to you!" he retorts.

Tegan made her first appearance in Doctor Who in the 1981 story Logopolis, which marked Tom Baker's final appearance as the Fourth Doctor. She then appeared in all but one story in the Fifth Doctor era between 1982 and 1984.

The Power of the Doctor reveals that Tegan hasn't seen or spoken to the Doctor in four decades, following her emotional exit from the TARDIS after a harrowing encounter with the Daleks in the story Resurrection of the Daleks.

Tegan bears some resentment for the Doctor never having reached out, but as the hologram takes the form of her old friend, they are able to reconcile. "You think you left and I never thought of you again?" asks the Doctor. "I never forget any of you. I remember everything."

"Yeah?" she says. "Well, what am I thinking seeing all these Cybermen?"

"Adric," the Doctor solemnly replies.

This exchange references the devastating events of the 1982 story Earthshock, the Fifth Doctor and Tegan's first encounter with the Cybermen, which ended in the tragic demise of fellow TARDIS traveller Adric, played by Matthew Waterhouse. (Admit it, Doctor Who fans, none of you had an Adric reference on your Doctor Who centenary special bingo card.)

The Doctor shares some familiar words of encouragement with Tegan ("Now, brave heart!") and encourages her to rally and escape the Cybermen – and with that, the hologram vanishes.

Speaking to Radio Times, Janet Fielding had previously described the reaction to news of Tegan's return to Doctor Who as "extraordinary" and "so enthusiastic", adding: "What can I say? How many shows give you that opportunity?"

Read more about Doctor Who:

• Jodie Whittaker says "rage" over Doctor Who casting was "terrifying"
• Doctor Who "would not exist" outside of the BBC, says Chris Chibnall
• Billie Piper: 'I'll treasure my time on Doctor Who for rest of my life'
• Doctor Who's Jodie Whittaker says Ncuti Gatwa will be "extraordinary"
• Doctor Who showrunner promises "very different" regeneration scene

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